P208 Efficacy of mogamulizumab in cutaneous T-cell lymphoma: a systematic review and meta-analysis

Abstract

Cutaneous T-cell lymphomas (CTCLs) are heterogeneous skin malignancies. Mycosis fungoides (MF) and Sézary syndrome (SS) are the most prevalent. Most systemic treatments produce sub­optimal responses. Mogamulizumab, an anti-CCR4 monoclonal antibody, demonstrated a superior overall response rate (ORR) compared with vorinostat in the MAVORIC phase III trial, leading to regulatory approval for relapsed or refractory MF and SS. However, its real-world efficacy remains poorly characterized. Currently, no systematic review has integrated the trial evidence with real-world data to estimate efficacy across clinical settings. The aim of this study was to synthesize clinical trial and observational data on the efficacy of mogamulizumab in CTCLs. We systematically searched PubMed, Embase and Cochrane CENTRAL (8 December 2025) for clinical trials and cohort studies reporting mogamulizumab monotherapy in CTCL. Primary outcomes were the CTCL ORR and ­subtype-specific ORRs in MF and SS. Single-arm proportions were pooled using a random effects meta-analysis of logit-transformed rates. Heterogeneity was assessed using the I2-statistic. The review was registered with PROSPERO (CRD420251171992). Of 1167 records, 6 studies were included (1 RCT, 2 single-arm interventional studies and 3 observational cohorts). These comprised 425 patients with CTCL with a median of three prior systemic therapies. The pooled ORR for CTCL was 40.4% [95% confidence interval (CI) 27.7–53.1; I2 = 86%). Subgroup analysis demonstrated a higher efficacy in SS (ORR 52.5%, 95% CI 34.8–70.3; I2 = 81.9%) than in MF (ORR 31.1%, 95% CI 20.7–42.1; I2 = 59.7%). Heterogeneity was partially attributable to disease stage, prior treatments and trial vs. real-world practices. Mogamulizumab demonstrates clinically meaningful efficacy in CTCL, with greater ORR in SS than MF, supporting its preferential use in patients with blood involvement. In SS, this pooled ORR compares favourably to the 2% ORR reported for vorinostat in the MAVORIC trial. These findings provide ­evidence-based guidance for the position of mogamulizumab within CTCL management. This is particularly relevant for SS, characterized by immune dysregulation, where substantial clinical efficacy is necessary to justify systemic immune modulation.